Molecular dynamics simulation of vacancy cluster formation in β- and α-Si3N4

被引：4

作者：

Adabifiroozjaei, E. ^{[1
]}

Mofarah, S. S. ^{[2
]}

Ma, H. ^{[2
]}

Jiang, Y. ^{[2
]}

Assadi, M. Hussein N. ^{[2
,3
]}

Suzuki, T. S. ^{[1
]}

机构：

[1] NIMS, RCFM, Tsukuba, Ibaraki 3050047, Japan

[2] UNSW Sydney, Sch Mat Sci & Engn, Sydney, NSW 2052, Australia

[3] NIMS, Ctr Green Res Energy & Environm Mat GREEN, 1-1 Namiki, Tsukuba, Ibaraki 3050044, Japan

来源：

COMPUTATIONAL MATERIALS SCIENCE | 2020年 / 178卷

基金：

日本学术振兴会;

关键词：

Silicon nitride; MD simulation; Vacancy cluster; SILICON-NITRIDE; DISLOCATION LOOPS; STABILITY; DEFECTS; CREEP;

D O I：

10.1016/j.commatsci.2020.109632

中图分类号：

T [工业技术];

学科分类号：

08 ;

摘要：

Molecular dynamics simulation is used to study vacancy cluster formation in beta- and alpha-Si3N4 with varying vacancy contents (0-25.6 at%). Vacancies are randomly created in supercells, which were subsequently heat-treated for 114 ns. The results show that both beta and alpha can tolerate vacancies up to 12.8 at% and form clusters, confirming previous experimental data indicating 8 at% vacancy in alpha-Si3N4. However, 25.6 at% vacancy in beta results in complete amorphization, while the same amount in alpha results in a transformation of a semi-amorphous a phase to a defective beta phase, leading to the removal of the clusters in newly formed beta. This clearly explains why cluster vacancies are not experimentally observed in beta, considering that beta-Si3N4 ceramics are produced from alpha. Furthermore, the lattice parameters of both modifications increase with increasing vacancy content, revealing the cause of different lattice constants that were previously reported for alpha-Si3N4.

引用

页数：6

共 31 条

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